how rare are A13 in oz

A12A or a real stamped A13... Neither are particularly common in OZ

It would seem by the number of responses that they are a rarity in Oz
I have one which I think was imported back in the 80's.
Ernie-- what do do you think would be more fun in a KB10-- the A13 with ovalport head or an A15?

mal ; the a13 have two types 73mm bore or 76mm,
which one do you have

I think the issue with the A13 is that they are all the tall a14/a15 block height with either 76mm bores and 70mm stroke or 73mm bores and 77mm stroke?. This would mean they both use 133mm rods with either 36mm 76mm slugs (heavy) or 32mm 73mm slugs. The trick would be to use a 140mm rod in the 76mm bore one with a15 pistons with 1mm taken off the top or isuzu gemini or mazda slugs. That would make 2:1 rods stroke ratio suited to high rpm providing all else is right but for the street big bore A15 is nice.

There are two A13s:
* Tall block (one year only North America)
* A12 block (was common in Japan and Asia markets)

Not too sure. Will have to check the block and see if it is a12 or a15 height

Not too sure. Will have to check the block and see if it is a12 or a15 height